Slide 1 / 152 Slide 2 / 152 5th Grade Decimal Computation 2015-10-08 www.njctl.org Slide 3 / 152 Decimal Computation Unit Topics Click on the topic to go to that section Decimal Addition · Decimal Subtraction · Multiplication of Multi-Digit Numbers · Decimal Multiplication · Mixed Word Problems · Glossary & Standards ·
Slide 4 / 152 Decimal Addition Return to Table of Contents Slide 5 / 152 Place Value Chart Slide 6 / 152 Place Value Chart A place value chart can be used to make subtraction easier. You will use your base-10 manipulatives to work out this problem. = 1 whole = 1 tenth = 1 hundredth
Place Value Chart Slide 7 / 152 0.21 + 1.04 = 1.25 (Click) (Click) (Click) + Slide 8 / 152 Place Value Chart On our paper, we can draw squares to represent 1 whole, lines to represent tenths, and small circles to represent hundredths. + 0.21 + 1.04 = 1.25 Slide 9 / 152 Place Value Chart 0.57 + .04 = ? What should we do with all of the ones? 7 + 4 = 11, Circle the goup of 10. + There is 1 tenth and 1 hundredth. Click to check. 0.57 + .04 = 0.61
Slide 10 / 152 1 Which place value model correctly represents 0.14 + 0.08? B A C D Slide 11 / 152 2 Use the place value chart to model the following problem. What is the answer? 0.05 + 0.71 = ? Slide 12 / 152 3 Use the place value chart to model the following problem. What is the answer? 2.35 + 0.17 = ?
Slide 13 / 152 4 Use the place value chart to model the following problem. What is the answer? 0.65 + 1.8 = ? Slide 14 / 152 5 Solve, then write your answer in standard form . Draw and use a place value chart to help you. 1 tenth + 1 and 2 tenths = ______ Slide 15 / 152 6 Solve, then write your answer in standard form. Draw and use a place value chart to help you. 35 thousandths + 8 thousandths = ______
Slide 16 / 152 7 Solve, then write your answer in standard form. Draw and use a place value chart to help you. 6 thousandths + 9 ones 5 thousandths = ______ Slide 17 / 152 Adding Decimals 0.25 0.25 0.25 0.25 Four quarters equal one dollar = $1.00 Slide 18 / 152 What is the Mistake? 0.25 0.25 0.25 0.25 1 + + $0.26
Slide 19 / 152 Adding Decimals Solve. 0.25 + 0.25 + 0.25 + 0.25 + 1.00 How could you make this problem easier to solve? Slide 20 / 152 Aligning Decimals When adding or subtracting decimals, always remember to align the decimals vertically... 0.25 0.25 0.25 0.25 1.00 + Can you explain why? It may help if you use the words "place value". Slide 21 / 152 Adding Decimals If you know how to add whole numbers then you can add decimals. Just follow these few steps. Step 1: Put the numbers in a vertical column, aligning the decimal points. Step 2: Add each column of digits, starting on the right and working left. Step 3: Place the decimal point in the answer directly below the decimal points that you lined up in Step 1.
Slide 22 / 152 Adding Decimal Example Now, try this - Don't forget - LINE 'EM UP 0.2 + 1.35 + 0.09 + 2.41 0.20 Why was a zero written here? 1.35 0.09 + 2.41 Slide 23 / 152 8 Find the sum: 0.3 + 0.47 Slide 24 / 152 9 Find the sum: 1.5 + 0.3
Slide 25 / 152 10 Find the sum: 0.7 + 0.06 + 1.5 Slide 26 / 152 11 Enter your answer in the box. 5.63 + 14.37 = From PARCC EOY sample test #22 Slide 27 / 152 12 Find the sum: 0.064 + 1.27 + 29.8
Slide 28 / 152 13 Find the sum: 10.7 + 107 + 1.07 + 0.107 Slide 29 / 152 Let's go to Cool Math and practice more addition: Cool Math Link click here Slide 30 / 152 14 Alice went bike riding at a park outside Newark. She biked 4.79 miles in the morning and 5.12 miles after lunch. How many miles did Alice bike in all?
Slide 31 / 152 15 Jeremy bought a jacket for $37.99 and a pair of jeans for $39.50. How much did Jeremy spend in all? Slide 32 / 152 16 On Friday, it rained 1.19 inches, and on Saturday, it rained 1.73 inches. How much did it rain on Friday and Saturday combined? Slide 33 / 152 17 Steven has $252.35 in his savings account. He makes deposits of $24.65 and $49.50. What is the new balance in his savings account?
Slide 34 / 152 18 Mr. Smith bought 3.5 pounds of ground beef and 2.485 pounds of sliced turkey. How many pounds of meat did he buy in all? Slide 35 / 152 19 The average temperature in May in Plainsville is 64.9 degrees F. This year the average temperature in May was 7.5 degrees higher than normal. What was the average temperature in Plainsville this May? Slide 36 / 152 20 Corey bought 86.2 grams of walnuts and 52.89 grams of chopped almonds. How many grams of nuts did he buy all together?
Slide 37 / 152 Use this Mathematical Practice pull tab for the next slide. Slide 38 / 152 21 A relay race consists of four sections. Teams A completes the first section in 112.5 seconds, the second section in 124.43 seconds, the third section in 97.82 seconds, and the last section in 103 seconds. How much time did it take Team A to run the entire relay race? Slide 39 / 152 Decimal Subtraction Return to Table of Contents
Slide 40 / 152 Slide 41 / 152 Subtracting Decimals A place value chart can be used to make subtraction easier. You will use your base-10 manipulatives to work out this problem. = 1 whole = 1 tenth = 1 hundredth Place Value Chart Slide 42 / 152 1.04 - 0.21 = 1.25 (Click) - What do we need to do? (Click above the arrow to reveal.)
Slide 43 / 152 Place Value Chart On our paper, we can draw squares to represent 1 whole, lines to represent tenths, and small circles to represent hundredths. + 1.04 - 0.21 =0.83 Slide 44 / 152 22 Which place value model correctly represents 0.71 - 0.05? A B - C D Slide 45 / 152 23 Use the place value chart to model the following problem. What is the answer? 2.31- 0.73 = ?
Slide 46 / 152 24 Use the place value chart to model the following problem. What is the answer? 2.35 - 0.17 = ? Slide 47 / 152 25 Use the place value chart to model the following problem. What is the answer? 1.8 - 0.65 = ? Slide 48 / 152 Subtracting Decimals Put the numbers in a vertical column aligning the decimal points. 1.2 - 0.8 Subtract the numbers from right to left using the same rules as whole numbers. 1 0 1.2 - 0.8 0.4
Slide 49 / 152 Subtracting Decimals What do we do if there aren't enough decimal places when we subtract? 5.2 - 3.08 Don't forget...Line 'em Up! 5.2 What goes here? 3.08 Remember, when subtracting, the largest number always goes on top. Slide 50 / 152 Subtracting Decimals One last thing to remember when subtracting numbers with decimals, is that the place value of the digits to the right of the decimal cannot be changed . Zeros cannot be deleted, unless they are the last digit(s). Example: .4080 - .3860 .0220 You cannot delete the zero in the tenths place. .0220 .220 However, you can delete the zero in the ten thousandths place. .0220 = .022 Slide 51 / 152 26 Find the difference 3.6 - 2.1
Slide 52 / 152 27 Find the difference 8.05 - 6.23 Slide 53 / 152 28 Find the difference 3.84 - 0.29 Slide 54 / 152 29 Find the difference 36.784 - 32
Slide 55 / 152 30 Find the difference 6.8 - 4.23 Slide 56 / 152 31 Find the difference 2 - 0.59 Slide 57 / 152 Let's go to Cool Math and practice subtraction. Cool Math Link click here
Slide 58 / 152 32 Frank's water bottle can hold 22.2 oz of water. Tim's bottle can hold 13.5 oz. How much more water can Frank's bottle hold? Slide 59 / 152 33 Josh threw a ball 15.53 meters. Trish threw a ball 16.49 meters. What is the difference between the two distances? Slide 60 / 152 34 Dennis ran 7.5 miles in the amount same time that Rita ran 5.73 miles. How many more miles did Dennis run than Rita?
Slide 61 / 152 35 McKenzie bought 14.32 gallons of gasoline. She used 9.63 gallons of gasoline on a trip to Jersey City. How much gasoline does McKenzie have left in her car? Slide 62 / 152 36 Donald weighted 192.4 pounds last year. He weighs 176.8 pounds this year. How much more did Donald weigh last year than this year? Slide 63 / 152 37 Maria ran the 200 meter dash in 29.152 seconds. Shelby ran the 200 meter dash in 28.901 seconds. How much longer did it take Maria to run the 200 meter dash than Shelby?
Slide 64 / 152 38 The original price of a plasma TV was $3,695.99. Barry bought the TV on sale for $2,499.50. How much did Barry save? Slide 65 / 152 39 On Monday, it rained 1.25 inches. On Wednesday, it rained 1.92 inches. How much more rain fell Wednesday than Monday? Slide 66 / 152 Multiplication of Multi-Digit Numbers Return to Table of Contents
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